Electronic part manufacturing method

ABSTRACT

Provided is a method of manufacturing an electronic part in which a circuit element ( 3 ) is formed on a surface of a ceramic substrate ( 1 ) and conductive balls ( 2 ) are used as terminals of the electronic part. After the ceramic substrate ( 1 ) and the conductive balls ( 2 ) are fixed, the ceramic substrate ( 1 ) is appropriately divided. For this, the manufacturing method includes: a first step of forming the circuit element(s) ( 3 ) on the surface of a large ceramic substrate ( 1 ) including division grooves ( 4 ) longitudinally and laterally provided on the surface thereof; a second step of fixing the conductive balls ( 2 ) to terminal portion of the circuit element(s) ( 3 ); and a third step of applying stress to the large ceramic substrate ( 1 ) to open the division grooves ( 4 ), to divide the substrate ( 1 ), and the first, second, and third steps are performed in the stated order. The stress to be applied in the third step is substantially equally applied to large number of conductive balls ( 2 ) or no stress is applied to the conductive balls ( 2 ).

TECHNICAL FIELD

The present invention relates to a method of manufacturing an electronicpart in which circuit elements are formed on a surface of a ceramicsubstrate and conductive balls are used as electronic part terminals.

BACKGROUND ART

An electronic part in which circuit elements are formed on a surface ofa ceramic substrate and conductive balls are used as electronic partterminals is disclosed in U.S. Pat. No. 6,326,677 and WO97/30461.

Mass production of the electronic part is required to ensure asufficient supply quantity when the electronic part is to be suppliedfor a similarly mass-produced electronic device. Therefore, in the caseof the electronic part (for example, a chip resistor) in which thecircuit elements are formed on the surface of the ceramic substrate,respective components of the circuit elements are formed for a largenumber of electronic parts by a thick-film technique or a thin-filmtechnique on a surface of a large ceramic substrate in which divisiongrooves are provided normally in advance. After that, the ceramicsubstrate is divided into respective electronic part units along thedivision grooves to realize the mass production.

-   Patent Document 1: U.S. Pat. No. 6,326,677-   Patent Document 2: WO 97/30461

DISCLOSURE OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

However, it is difficult to realize the mass production of theelectronic part in which the circuit elements are formed on the surfaceof the ceramic substrate and the conductive balls are used as theelectronic part terminals. This is because the electronic part includesthe ceramic substrate and the conductive balls fixed thereto.

If the conductive balls are fixed to the ceramic substrate before adivision step and then the division step is to be performed in such astate, excessive stress may be concentrated on a fixed portion betweenthe ceramic substrate and the conductive ball during the division step.As a result, peeling is caused between the ceramic substrate and theconductive ball. Therefore, it is likely that does not operate as theelectronic part. In present technology, there are two typical one as thestress. One is a stress performed so as to bend the ceramic substrate ina direction in which the divisi on groove is opened. The other is astress based on a vibration caused during a cutting step for dicing theceramic substrate.

If the conductive balls are to be fixed to the ceramic substrate afterthe division step, it is necessary to perform, for example, an operationfor putting integrally formed parts in matrix again. As a result, amanufacturing process is further complicated. Therefore, this isunsuitable for the mass production of the electronic part.

Thus, in order to solve the problems, an object of the present inventionis to perform a suitable division of the ceramic substrate after theconductive balls are fixed to the ceramic substrate.

MEANS FOR SOLVING PROBLEMS

In order to solve the above-mentioned problems, a first method ofmanufacturing an electronic part in which a circuit element 3 is formedon a surface of a ceramic substrate 1 and conductive balls 2 are used asterminals of the electronic part, includes: a first step of forming acircuit element 3 on the surface 1 of the large ceramic substrateincluding division grooves 4 longitudinally and laterally provided onthe surface thereof; a second step of fixing the conductive balls 2 toterminal portions of the circuit element 3; and a third step of applyingstress to the substrate 1 to open the division grooves 4, to divide thesubstrate 1, the first, second, and third steps being performed in thestated order, and is characterized in that the whole stress to beapplied in the third step is substantially equally applied to a largenumber of conductive balls 2, or the whole stress is applied to thesubstrate 1 and/or the circuit element 3, or a part of the stress issubstantially equally applied to a large number of conductive balls 2and a remainder of the stress is applied to the substrate 1 and/or thecircuit element 3.

In view of mass production, it is particularly preferable to perform amethod of forming the circuit element 3 in the first step using screenprinting. The circuit element 3 is a resistor element, a condenserelement, an inductor element, a multiple element or a network element inwhich a large number of one kind of those are included in a singleelectronic part, a composite element represented by a CR part in which acombination of two or more kinds of those is included in a singleelectronic part, or the like.

When the conductive balls 3 are to be fixed with the terminal portionsof the circuit element 3 in the second step, it is possible to use anavailable ball grid array (BGA) type ball placement system forelectronic part or the like in a state in which cream solder or the likeis screen-printed to a position to be fixed, for example.

Here, instead of the cream solder, a conductive bonding agent in which,for example, a silver material or a carbon material is dispersed inepoxy resin paste or the like can be preferably used. Because resin issofter than metal, even when the stress is applied to the conductiveballs 2, the stress can be absorbed by the resin. Therefore, there is anadvantage in that fixation between the substrate 1 and the conductiveball 2 is not easily reduced by the stress applied during the divisionstep.

When the stress is to be substantially equally applied to a large numberof conductive balls 2 in the third step, for example, as shown in FIGS.1 and 2, a buffer member 5 made of styrene foam, sponge, cloth, rubber,resin, or the like is placed on the large number of conductive balls 2to apply the stress to the large number of conductive balls 2 throughthe buffer member 5. Because of the presence of the buffer member 5, apart of or the entire applied stress does not concentrate on one of or asmall number of conductive balls 2 and the stress is dispersed to thelarge number of conductive balls 2. As a result, there is a first effectin which the ceramic substrate 1 and a specific conductive ball 2 areprevented from peeling. Alternatively, a part of or the entire stress isapplied to the substrate 1 and/or the circuit element 3. As a result,there is a second effect in which the stress is not applied to theconductive balls 2 and thus the ceramic substrate 1 and the specificconductive ball 2 are prevented from peeling. In some cases, one of orboth the first effect and the second effect are obtained.

In the above description, “large number” included in “large number ofconductive balls” corresponds to a number to the extent to which afixation state between the conductive ball 2 and the substrate 1 is notsubstantially affected even when the stress is substantially equallyapplied to all those. Therefore, the number of conductive balls ischanged based on a stress condition, the fixation state, a diameter ofeach of the conductive ball 2, a size of the substrate 1, a depth ofeach of the division grooves 4, and the like. However, the number isnormally substantially equal to or larger than one-fourth of a totalnumber of the conductive balls 2 fixed to the substrate 1.

Flexibility of the buffer member 5 may be lower than rigidity of theceramic substrate 1, may follow a warp of the substrate 1 before it isdivided, and may be the extent to which the buffer member 5 is notbroken. Therefore, even when a member is recognized to be a “rigid body”based on the generally-accepted idea, the member may become the “buffermember 5” in some cases. For example, a phenol resin, a hard rubber, orthe like may become the “buffer member 5”.

As shown in FIG. 2, it is preferable that the buffer member 5 have aportion which is in contact with an end surface of the substrate 1. Thisis because, during an operation for fitting the substrate 1 to thebuffer member 5, the portion acts to prevent the positions of both fromdisplacing and thus is advantageous. In addition, this is because acontact portion between the end surface and the buffer member 5 canabsorb the stress applied to the conductive balls 2 in a lateraldirection (direction parallel to the surface of the substrate 1) tofurther make a stress dispersion effect to the buffer member 5. In orderto obtain the same effect, the substrate 1 has a portion extending fromthe end surface of the substrate in a direction substantiallyperpendicular to the surface of the substrate 1. Therefore, the buffermember 5 can also be mounted on the surface of the substrate 1 while thebuffer member is fit to the portion of the substrate so as to be incontact with the portion thereof. That is, when the buffer member 5 andthe substrate 1 are to be fit, a fitting side and a side to be fit canbe reversed to each other.

As shown in FIG. 2, it is preferable that an area of a portion whichbecomes a convex portion of the buffer member 5 relative to the presenceof a concave portion 6 thereof is larger than that of the concaveportion 6. This is because the extent to which the stress issubstantially dispersed through the convex portion may be large.

To prevent the conductive balls 2 from the stress in the third step, forexample, the stress is applied only to the ceramic substrate 1. Besidethis, the stress is applied to, for example, only the circuit element 3or the circuit element 3 and the ceramic substrate 1. Even in such thecase, there is an effect in which the ceramic substrate 1 and thespecific conductive ball 2 are prevented from peeling. To be morespecific, as shown in FIG. 2, a stress applying jig (such as the buffermember 5) is formed in a grid shape so as to avoid a contact with theconductive balls 2. The grid shape portion is formed, for example, to becontact with the ceramic substrate 1 only and/or the circuit element 3only.

In an example in which, in the third step, a part of the stress issubstantially equally applied to the large number of conductive balls 2and the remainder of the stress is applied to the ceramic substrate 1and/or the circuit element 3, there is, for example, a structure inwhich a rosin material such as flux is injected between the conductiveballs 2 above the surface of the substrate 1. The rosin material mayexist at a height which exceeds that of a top portion of the conductiveball 2 or may exist at a height which is lower than that of the topportion. The rosin material has both a bonding effect and a bufferingeffect, so the fixation between the conductive ball 2 and the substrate1 is enhanced and the stress directly applied to the specific conductiveball 2 is transferred to the vicinity thereof to substantially equallyapply the stress to the large number of conductive balls 2. Therefore,the rosin material has the same operation as that of the buffer material5. The buffering effect becomes significant in a case where the rosinmaterial exists at a height which exceeds that of the top portion of theconductive ball 2. This is because it is difficult to directly apply thestress to the specific conductive ball 2.

After the division step is completed, the rosin material can be removedby cleaning using, for example, alcohol, ketone such as acetone, orethyl acetate, that is, an organic solvent. When a material which can beremoved after the division step instead of the rosin material isinjected between the conductive balls 2 above the surface of thesubstrate 1, the same operation as that of the rosin material can bemade.

According to the first manufacturing method, the ceramic substrate 1 canbe suitably divided after the conductive balls 2 are fixed to theceramic substrate 1. Here, the word “suitably” means that, for example,the ceramic substrate 1 and the conductive balls 2 are prevented frompeeling.

In order to solve the above-mentioned problems, a second method ofmanufacturing an electronic part in which a circuit element 3 is formedon a surface of a ceramic substrate 1 and conductive balls 2 are used asterminals of the electronic part, includes: an eleventh step of forminga circuit element 3 on the surface of the large ceramic substrate 1; atwelfth step of fixing the conductive balls 2 to terminal portions ofthe circuit element 3; a thirteenth step of forming division grooves 4for the substrate 1 on the surface of the substrate 1 on which thecircuit element 3 exists; and a fourteenth step of applying stress tothe substrate 1 to open the division grooves 4, to divide the substrate1, the eleventh, twelfth, thirteenth, and fourteenth steps beingperformed in the stated order, and is characterized in that the wholestress to be applied in the fourteenth step is substantially equallyapplied to a large number of conductive balls 2, or the whole stress isapplied to the substrate 1 and/or the circuit element 3, or a part ofthe stress is substantially equally applied to a large number ofconductive balls 2 and a remainder of the stress is applied to thesubstrate 1 and/or the circuit element 3.

The eleventh step substantially corresponds to the first step in thefirst manufacturing method. The twelfth step corresponds to the secondstep in the first manufacturing method. The fourteenth step correspondsto the third step in the first manufacturing method.

A difference between the eleventh step and the first step resides inwhether or not the division groove 4 is formed in advance on the surfaceof the ceramic substrate 1. Although the division groove 4 is not formedin advance on the surface of the ceramic substrate 1 in the eleventhstep, the division groove 4 is formed in the later thirteenth step. Sucha forming method is based on, for example, dicing processing. Unlike thecutting and division step for dicing the ceramic substrate 1, the dicingprocessing is processing for forming a slight shallow groove on thesurface of the ceramic substrate 1 without completely cutting theceramic substrate 1. Therefore, because of a vibration caused during theprocessing, there is no case where excessive stress concentrates on afixed portion between the ceramic substrate 1 and each of the conductiveballs 2. In processing until the ceramic substrate 1 is cut, although ablade such as a dicing blade is used, the blade significantly wears.This is because the ceramic substrate 1 is made of a very hard material.However, in the processing for forming the slight shallow groove on thesurface of the ceramic substrate 1, the wear is not so significant.

Therefore, in view of mass production of the electronic part as in thecase of the present invention, the above-mentioned method may be asuitable method of forming the division groove 4.

The advantage of forming the division groove 4 after the formation ofthe circuit element 3 in the thirteenth step is that, even when thecircuit element 3 is formed in any position, the division groove 4 canbe formed in a suitable position based on a formation of the circuitelement 3. If the ceramic substrate 1 is subjected to the grooveformation before the formation of the circuit element 3, a difficulty onforming the circuit element 3 becomes very large. This is because it isnot acceptable to form the circuit element 3 whose position isdisplaced.

When the rosin material or the like is used for the buffer member 5 inthe thirteenth step, it is preferable to form the division groove 4after the rosin material is injected between the conductive balls 2above the surface of the substrate 1 and hardened. When the abovedescribed division groove 4 is formed, the buffer member 5 is cut alongthe division groove 4 at the same time. In this case, there is anadvantage in that the stress applied at the time of division is small.This reason is that, the presence of the rosin material or the like maybecome a divisional hindrance, so the hindrance can be removed by thecutting.

In the first and second manufacturing methods, it is preferable that thesurface of the ceramic substrate 1 on which the circuit element 3 isformed, and the surface on which the division groove 4 exists, are thesame surface. In the first manufacturing method, this is because apositional relationship with the division groove 4 can be visuallychecked in the step of forming the circuit element 3 (first step). Inthe second manufacturing method, this is because a positionalrelationship with the circuit element 3 can be visually checked in thestep of forming the division groove 4 (thirteenth step). In the firstand second manufacturing methods, when the stress is applied in adirection in which the division groove 4 is opened and the division isperformed along the division groove, there is an advantage of that theconductive balls 2 adjacent to each other which place the groove betweendon't knock against each other.

EFFECT OF THE INVENTION

According to the present invention, the ceramic substrate can besuitably divided after the conductive balls are fixed to the ceramicsubstrate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 A perspective view according to the present invention, showing anexample of an outline of a state in which a buffer member is fit to asurface of a large substrate on which circuit elements and conductiveballs are formed and arranged such that a concave portion is alignedwith positions of the conductive balls.

FIG. 2 A partially sectional view according to the present invention,showing an example of an outline of a state in which the buffer memberis fit to the large substrate on which the circuit elements theconductive balls are formed and arranged.

FIG. 3 A state showing which stress is applied so as to bend the largesubstrate when the large substrate is placed on a belt and passesbetween rollers.

FIG. 4 An example of an embodiment of the present invention, whichsequentially shows states in which a circuit structure of a singleelectronic part is formed. FIG. 5 An example of an embodiment of thepresent invention, which sequentially shows states in which theconducive balls are fixed onto lands of the substrate.

DESCRIPTION OF REFERENCE NUMERALS

-   1 substrate-   2 conductive ball-   3 circuit element-   4 division grooves-   5 buffer member-   6 concave portion-   7 land, electrode-   8 roller-   9 belt-   13 resistor-   14 glass film-   16 overcoat-   19 fluxes-   20 common electrode

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment of First Manufacturing Method)

An example of a best mode for carrying out the present invention basedon the first manufacturing method will be described below.

A large alumina ceramic substrate 1 having a thickness of 0.5 mm, whichis molded so as to longitudinally and laterally form a large number ofdivision grooves 4 on a surface thereof in advance and which has beensubjected to a sintering step is prepared. Each of minimum unitsubstrates 1 obtained after division along the division grooves 4becomes a single electronic part. A process for forming circuit elements3 and the like on the surface of the large alumina ceramic substrate 1having the grooves will be described below with reference to thedrawings. In the drawings, the minimum unit substrate 1 is shown.

First, an Ag—Pd conductive paste containing a glass frit isscreen-printed on the surface of the substrate 1 on which the divisiongrooves 4 are formed and then baked to obtain lands 7 that holdelectrodes for circuit elements 3 concurrently and lands 7 that holdcommon electrodes 20 for circuit elements 3 concurrently (FIG. 4(a)).Next, a metal glaze resistor paste containing mainly a ruthenium oxideand a glass frit is screen-printed so as to be in contact with both thecommon electrode 20 and the electrode 7 and then baked to obtainresistors 13 (FIG. 4(b)). Then, a glass paste is screen-printed so as tocover the resistors 13 and then baked the substrate so as to obtainglass films 14 (FIG. 4(c)). Then, in order to set a resistance value ofa resistor element which is composed of the electrode 7, the commonelectrode 20, and the resistors 13 to a desirable value, a step offorming trimming grooves on the resistors 13 by laser irradiation toadjust the resistance value is performed (FIG. 4(d)). At this time, theglass films 14 act to minimize damage to all parts of the resistors 13.Then, an overcoat 16 serving as a protective film is screen-printedusing an epoxy resin paste so as to protect all the resistor element andthen the epoxy resin paste is hardened by heating (FIG. 4(e)). When theovercoat 16 is placed, land 7 portions necessary for the electrode 7 andthe common electrode 20 are exposed (FIG. 4(e)). After that, the firststep is completed. Note that the circuit element 3 structure of thesingle electronic part as shown in FIG. 4 is different from the circuitelement 3 structure shown in FIG. 1 and a so-called network resistor isconstructed by the entire electronic part.

Next, high-viscosity fluxes 19 are located on the lands 7 obtained bythe formation of the overcoat 16 (FIG. 5(a)). The fluxes 19 to be usedare produced by Senju Metal Industry Co., Ltd. (product name:Deltalux529D-1). The locating method is a pin transfer method. Attentionat the time of location is that each of the fluxes 19 is within a land 7region and exists in a region narrower than the land 7 region. The pintransfer method used here is a method of bringing the flux into contactwith a tip of a needle member and speedily bringing the tip into contactwith an upper portion of the land 7 to apply the flux adhered to the tipto the land.

Instead of the pin transfer method, a screen printing method, a balltransfer method using the conductive ball 2 instead of the pin, adispenser method, or the like can be employed. Instead of the flux 19(product name: Deltalux529D-1), a flux having a viscosity or an adhesionproperty which is equal to that of the flux 19 can be used.

Next, the conductive ball 2 is located using an available ball placementsystem (FIG. 5(b)) and then the land 7 and the conductive ball 2 arefixed to each other (FIG. 5(c)). The conductive ball 2 has a surfacelayer made of tin (so-called lead-free solder) and a core made ofcopper. The fixing process is based on a known reflow step. The secondstep ends above described.

Next, as is apparent from the outline shown in FIGS. 1 and 2, the buffermember 5 made of a hard rubber is fit to the surface of the largesubstrate 1 to which the conductive balls 2 are fixed and then fixed tothe substrate. The buffer member 5 has the concave portion 6corresponding to a portion in which each of the conductive balls 2exists. The concave portion 6 houses the conductive ball 2 so as tocover upper and surrounding portions thereof. The buffer member 5 has ashape in which a portion which becomes the convex portion relative tothe presence of the concave portion 6 is in contact with the surface ofthe ceramic substrate 1 and/or the circuit element 3. As shown in FIG.2, the buffer member 5 has the portion which is in contact with the endsurface of the substrate 1. Therefore, even when an upper surface of thebuffer member 5, that is, a smooth surface opposed to a smooth surfaceof the large substrate 1 which is the fixed state is slightly pressed,the stress to be applied does not concentrate on one or a small numberof conductive balls 2. Thus, the stress is dispersed to the large numberof conductive balls 2 located around the pressed portion.

With such a state, the stress is applied in the direction in which thedivision groove 4 is opened. As shown in FIG. 3, the application of thestress is realized by passing a work body in which the buffer member 5is fit to the large substrate 1 between rollers 8 while the work body isplaced on a belt 9. In this case, the division is performed along thelongitudinal or lateral division grooves 4 formed on the surface of thesubstrate 1. After the division is completed, the division is performedalong only the other direction. This is because it may be difficult tosimultaneously perform the division along both the longitudinal andlateral division grooves 4. The third step ends above described.

As a result, there was no case where peeling was caused between thesubstrate 1 and each of the conductive balls 2. In addition, there wasno case where, although the peeling was not caused, the fixation betweenthe substrate 1 and the conductive ball 2 reduced.

(Embodiment of Second Manufacturing Method)

An example of a best mode for carrying out the present invention basedon the second manufacturing method will be described below.

Except for the use of the substrate 1 on which the division grooveshaven't been formed in advance, a step with the same condition as thatof the first step and a step with the same condition as that of thesecond step in the embodiment mode of the first manufacturing method areperformed. The eleventh and twelfth steps in the second manufacturingmethod ends above described.

Then, the division grooves 4 are formed on the surface of the substrate1 on which the circuit elements 3 are formed. The formation of thedivision grooves 4 is based on dicing using a dicing saw in whichdiamond powders are adhered to the surface thereof. The dicing isperformed using an available tool and an available apparatus on themarket. When the division grooves 4 are formed by the dicing, apositional relationship between the division grooves 4 and the circuitelements 3 is adjusted such that a large number of division grooves 4are longitudinally and laterally formed on the surface of the substrate1 and a segment surrounded by the division grooves 4 becomes a singleelectronic part. The thirteenth step in the second manufacturing methodends above described.

The buffer member 5 used in the third step in the embodiment of thefirst manufacturing method is used as in the embodiment thereof and thedivision step is performed. The fourteenth step in the secondmanufacturing method ends above described.

As a result, as in the embodiment of the first manufacturing method,there was no case where peeling was caused between the substrate 1 andeach of the conductive balls 2. In addition, there was no case where,although the peeling was not caused, the fixation between the substrate1 and the conductive ball 2 reduced.

(Other Embodiments)

In the above-mentioned first and second embodiments, the conductiveballs 2 are fixed to the land 7 located on the surface of the largesubstrate 1 on which the circuit elements 3 are formed. However, theconductive balls 2 may be fixed to a surface opposed to the surface ofthe large substrate 1 on which the circuit elements 3 are formed. Insuch the case, it is necessary to provide, for example, a via hole formaking electrical connection between both surfaces of the substrate 1.In addition, it is necessary to locate the buffer member 5 on thesurface of the substrate 1 to which the conductive balls 2 are fixed.

In the above-mentioned first and second embodiments, the divisiongrooves 4 exist on the surface of the large substrate 1 on which thecircuit elements 3 are formed. However, the division grooves 4 may existon the surface opposed to the surface of the large substrate 1 on whichthe circuit elements 3 are formed. Note that, in view of the divisionwhich is normally performed in the direction in which the divisiongroove 4 is opened, when a part of the circuit elements 3 is formedacross the adjacent unit electronic parts, it is likely to cause peelingfrom the substrate 1 including the part thereof. Therefore, a structurein which the division grooves 4 exist on the surface of the largesubstrate 1 on which the circuit elements 3 are formed may be a morepreferable structure.

In the above-mentioned first and second embodiments, when the conductiveball 2 is fixed to the land 7, only the high-viscosity flux 19 isinterposed therebetween. However, for example, when the conductive ball4 is made of a copper material in which solder does not exist on thesurface thereof, it is preferable to interpose cream solder instead ofor together with the high-viscosity flux 19 and perform a reflow step orthe like. A condition suitable for the fixing can be selected based on amaterial of the surface of the conductive ball 2 and a material of theland 7. If necessary, the surface of the land 7 can be solder-plated toimprove the surface of the land 7 so as to adhere solder easily. Aconductive bonding agent can be used as a member for fixing theconductive ball 2 to the land 7 without the use of the solder.

In the above-mentioned first and second embodiments, the surface layerof conductive ball 2 is made of tin, so-called lead-free solder. Forexample, when lead-contained solder whose weight ratio of lead and tinis 95:5 is used, a heat cycle characteristic can be improved with theviscosity of the lead. When the lead-free solder is used in view ofenvironmental harmony, an Sn—Bi alloy, an Sn—In—Ag alloy, an Sn—Bi—Znalloy, an Sn—Zn alloy, an Sn—Ag—Bi alloy, an Sn—Bi—Ag—Cu alloy, anSn—Ag—Cu alloy, an Sn—Ag—In alloy, an Sn—Ag—Cu—Sb alloy, an Sn—Ag alloy,an Sn—Cu alloy, or an Sn—Sb alloy can be used in addition to the use ofonly Sn as the above-mentioned embodiments.

INDUSTRIAL APPLICABILITY

According to the present invention, there is applicability in industriesassociated with an electronic part in which circuit elements are formedon a surface of a ceramic substrate and conductive balls are used asterminals of the electronic part.

1. A method of manufacturing an electronic part in which at least onecircuit element is formed on a surface of a ceramic substrate andconductive balls are used as terminals of the electronic part,comprising: a first step of forming at least one circuit element on thesurface of a large ceramic substrate including division grooveslongitudinally and laterally provided on the surface thereof; a secondstep of fixing the conductive balls to terminal portions of the circuitelement; and a third step of applying stress to the large ceramicsubstrate to open the division grooves, to divide the substrate, thefirst, second, and third steps being performed in the stated order,wherein the stress to be applied in the third step is substantiallyequally applied to a large number of conductive balls, or the stress isapplied to the substrate and/or the circuit element, or a part of thestress is substantially equally applied to a large number of conductiveballs and a remainder of the stress is applied to the substrate and/orthe circuit element.
 2. (canceled)
 3. A method of manufacturing anelectronic part according to claim 1, wherein the third step isperformed in a state in which a buffer member having a concave portionis located on the surface of the large ceramic substrate to whichconductive balls are fixed to house the conductive balls in the concaveportion and a portion of the buffer member which becomes a convexportion relative to a presence of the concave portion is on contact withthe surface of the substrate and/or the circuit element.
 4. A method ofmanufacturing an electronic part according to claim 1, wherein thedivision grooves exist on the surface of the substrate to whichconductive balls are fixed.
 5. (canceled)
 6. A method of manufacturingan electronic part according to claim 1, wherein the conductive ballsare fixed to the substrate using a conductive bonding agent.
 7. A methodof manufacturing an electronic part in which at least one circuitelement is formed on a surface of a ceramic substrate and conductiveballs are used as terminals of the electronic part, comprising: a firststep of forming at least one circuit element on the surface of a largeceramic substrate; a second step of fixing the conductive balls toterminal portions of the circuit element; a third step of formingdivision grooves for the large ceramic substrate on the surface of thesubstrate on which the circuit element exists; and a fourth step ofapplying stress to the large ceramic substrate to open the divisiongrooves, to divide the substrate, the first, second, third and fourthsteps being performed in the stated order, wherein the stress to beapplied in the fourth step is substantially equally applied to a largenumber of conductive balls, or the stress is applied to the substrateand/or the circuit element, or a part of the stress is substantiallyequally applied to a large number of conductive balls and a remainder ofthe stress is applied to the substrate and/or the circuit element.
 8. Amethod of manufacturing an electronic part according to claim 7, whereinthe fourth step is performed in a state in which a buffer member havinga concave portion is located on the surface of the large ceramicsubstrate to which conductive balls are fixed to house the conductiveballs in the concave portion and a portion of the buffer member whichbecomes a convex portion relative to a presence of the concave portionis on contact with the surface of the substrate and/or the circuitelement.
 9. A method of manufacturing an electronic part according toclaim 7, wherein the division grooves exist on the surface of thesubstrate to which conductive balls are fixed.
 10. A method ofmanufacturing an electronic part according to claim 7, wherein theconductive balls are fixed to the substrate using a conductive bondingagent.
 11. A method of manufacturing an electronic part according toclaim 1, wherein the division grooves exist on the surface of thesubstrate on which the circuit element is formed.